Why?
• Meet other local OSM Mappers and the PSU students that are working on OSM improvements in the 4-county regional area.
• Observe our OSM editing process first hand and provide feedback: it is a manual and labor intensive process, it is not a data import. We are using up-to-date regional jurisdictional data and 6-inch ortho-rectified digital imagery flown in August 2010 as a reference with permission from the sources.
• Learn why we chose to invest in OSM and the community, rather than a proprietary mapping solution.
• See a sneak preview of the Open Trip Planner, TriMet's new open source multi-modal trip planner scheduled for release in Fall, and meet the developers involved in the project.
• Explore opportunities for collaboration and on-going maintenance (ex: local cities and counties can make street data available to the OSM community).

This event seems to be really publicized. There were 4-5 diary entries about this; I even got sent a personal message about it even though I don't live in Portland, I live in Seattle (about 2-3 hrs North). But I agree with seav; I like the fact that govt agencies are supporting OSM.